N-Queens
op: puzzles.n_queens.solvePlace N queens on an N×N board so no two attack each other. Projection: each row is a column-eigenstate; locked queens project out conflicting columns + diagonals from all other rows.
board size N
Place N queens on an N×N board so no two attack each other. Projection: each row is a column-eigenstate; locked queens project out conflicting columns + diagonals from all other rows.